Clamshell apparatus for electrochemically treating semiconductor wafers

ABSTRACT

An apparatus for electroplating a wafer surface includes a cup having a central aperture defined by an inner perimeter, a compliant seal adjacent the inner perimeter, contacts adjacent the compliant seal and a cone attached to a rotatable spindle. The compliant seal forms a seal with the perimeter region of the wafer surface preventing plating solution from contaminating the wafer edge, wafer backside and the contacts. As a further measure to prevent contamination, the region behind the compliant seal is pressurized. By rotating the wafer during electroplating, bubble entrapment on the wafer surface is prevented. Further, the contacts can be arranged into banks of contacts and the resistivity between banks can be tested to detect poor electrical connections between the contacts and the wafer surface.

CROSS REFERENCE TO RELATED APPLICATION

This application is related to Contolini et al., co-filed applicationSer. No. 08/970,120, pending, Reid et al., co-filed application Ser. No.08/969,267, pending, and Reid et al., co-filed application Ser. No.08/969,196, pending, all of which are incorporated herein by referencein their entirety.

FIELD OF THE INVENTION

The present invention relates generally to a method and apparatus fortreating the surface of a substrate and more particularly to a methodand apparatus for electroplating a layer on a semiconductor wafer.

BACKGROUND OF THE INVENTION

The manufacture of semiconductor devices requires the formation ofelectrical conductors on semiconductor wafers. For example, electricallyconductive leads on the wafer are often formed by electroplating(depositing) an electrically conductive material such as copper on thewafer and into patterned trenches.

Electroplating involves making electrical contact with the wafer surfaceupon which the electrically conductive material is to be deposited(hereinafter the "wafer plating surface"). To insure a uniformdeposition, it is important that the electrical contact with the waferplating surface be uniform and reliable.

Brogden et al., U.S. Pat. No. 5,227,041 (hereinafter Brogden), teaches adry contact electroplating apparatus wherein a number of electricalcontacts are provided adjacent to a central aperture of a base of theapparatus. Brogden further teaches that the contacts preferably includerelatively sharp tips for piercing any insulating substance which may bepresent on the wafer plating surface. However, even with relativelysharp tips, one or more of the contacts may form a poor electricalconnection with the wafer plating surface. This results in nonuniformityof the deposited electrically conductive layer. To determine if one ormore poor electrical connections were made with the wafer platingsurface, the wafer can be tested to measure the uniformity of thedeposited electrically conductive layer. However, wafers exhibitingnonuniformity of the deposited electrically conductive layer must bediscarded reducing the yield of the electroplated wafers. Further, it isnot practical or cost effective to test every wafer. Thus, it isdesirable to have an apparatus for electroplating a wafer which providesuniform electrical contact with the wafer plating surface while at thesame time providing a means of readily testing the integrity of theelectrical contact with the wafer plating surface before the wafer iselectroplated.

Electroplating also requires immersion of the wafer in a platingsolution (i.e. a solution containing ions of the element beingdeposited, for example a solution containing Cu⁺⁺). It is important toprevent contamination of the wafer backside (i.e. the surface of thewafer opposite the wafer plating surface) and the wafer edge from theelectrolyte (the ions of the element being deposited).

One conventional method of preventing contamination is to use acorrosive solvent immediately following the electroplating to removecontaminants from the wafer backside and the wafer edge. While thismethod is satisfactory, it requires an extra processing step and the useof hazardous chemicals. A more effective method is to preventcontamination of the wafer backside and the wafer edge in the firstplace. Accordingly, it is desirable to have an apparatus forelectroplating a wafer which avoids contamination of the wafer backsideand the wafer edge at any time during the process.

Brogden (cited above) teaches an electroplating apparatus which reducescontamination of the wafer backside and wafer edge during theelectroplating process. Referring to FIG. 2 of Brogden, a sealing ring40 positioned inside electrical contacts 36 forms a sealing connectionwith the wafer so that contacts 36 and the wafer backside and edge arenot exposed to the plating solution. However, particulates andnonuniformities may result in a poor sealing connection with the waferallowing plating solution to leak past sealing ring 40 to contaminatecontacts 36 and the wafer backside and edge. In the event of leakage,the electroplating apparatus must be serviced and the wafer may have tobe discarded. Accordingly, the art needs a dry contact electroplatingapparatus which eliminates possible leakage of the plating solution andavoids the associated contamination of the contacts and wafer backsideand edge.

Another difficulty with immersing the wafer in a plating solution isentrapment of air bubbles on the wafer plating surface. Air bubblesdisrupt the flow of electrolytes and electrical current to the waferplating surface creating nonuniformity in the deposited layer. Oneconventional method of reducing air bubble entrapment is to immerse thewafer vertically into the plating solution. However, mounting the wafervertically for immersion into the plating solution adds complexity andhinders automation of the electroplating process. Accordingly, it isdesirable to have an apparatus for electroplating a wafer which avoidsair bubble entrapment and which is automated.

SUMMARY OF THE INVENTION

In accordance with the present invention, an apparatus for treating aplating surface of a substrate, typically a wafer, includes a cup havinga central aperture defined by an inner perimeter, a compliant sealadjacent the inner perimeter, a plurality of contacts adjacent thecompliant seal and a cone attached to a rotatable spindle.

When the cup is clamped to the cone, an O-ring in the pressing surfaceof the cone presses against the backside of the wafer. This forms a sealbetween the O-ring and the backside of the wafer and also between thecompliant seal and a perimeter region of the plating surface of thewafer while simultaneously forming the electrical connection between theplurality of contacts and the plating surface. The seal with the platingsurface prevents the plating solution from contacting the wafer edge,the wafer backside and the plurality of contacts and thus prevents theassociated electrolyte contamination. As a secondary measure to preventelectrolyte contamination, the region behind the compliant seal ispressurized thus preventing the plating solution from leaking past thecompliant seal. Further, any leak in the seal with the plating surfacecan be readily detected by monitoring for any escape of the pressurizedgas in the region behind the compliant seal.

Mounting the cone on a rotatable spindle advantageously allows theassembly of the cone, cup and wafer to be rotated after the assembly isimmersed in the plating solution. This prevents bubble entrapment on thewafer and improves electrolyte transport to the wafer which, in turn,improves the uniformity of the electroplated layer. Further, thethickness profile of the electroplated layer can readily be adjusted bychanging the rotational speed of the assembly.

The plurality of contacts can be grouped into banks of contactselectrically isolated from one another. In this manner, after theelectrical connection between the plurality of contacts and the platingsurface is established, continuity in resistances between the banks ofcontacts can be checked to readily detect if any poor electricalconnections were made.

In accordance with the present invention, a method of depositing anelectrically conductive layer on the wafer includes providing the waferhaving an electrically conductive seed layer on a first surface of thewafer. The wafer is then placed first surface down into the cup and thecup is then clamped to the cone thus establishing the electricalconnection between the plurality of contacts and the seed layer. The cupis then placed into the plating solution thus exposing a portion of theseed layer to the plating solution. The cup and wafer are then rotatedand voltage is applied to the plurality of contacts thus depositing theelectrically conductive layer on the seed layer.

In accordance with the present invention, a rotary union for use with anelectroplating apparatus includes a shaft having a first surface areaand an extended surface area, the first surface area having a firstaperture therein, the extended surface area having a second aperturetherein. The rotary union further includes an outer face seal and aninner face seal. The outer face seal is pressed against, and forms aseal with, the first surface area. The inner face seal is pressedagainst, and forms a seal with, the extended surface area. A pressurepassage coupled to the first aperture passes through the outer face sealand around the outside of the inner face seal. A pressure/vacuum passagecoupled to the second aperture passes through the inner face seal.

The rotary union has a lower connector or a lower connector incombination with a tube connector which allows the pressure/vacuumpassage to be coupled to an inner coaxial tube and the pressure passageto be coupled to an outer coaxial tube. Of importance, this allows bothvacuum and pressure to be provided through the inner and outer coaxialtubes, respectively, to a rotating clamshell of the electroplatingapparatus. Since the inner and outer coaxial tubes share a common axis(the inner tube being inside of the outer tube), the space required forthe tubing is reduced to that of the outer coaxial tube compared tohaving both the inner and outer tubes in a side by side arrangement.This is particularly advantageous for use in an electroplating apparatusin accordance with the present invention wherein size constraints of thepressure and vacuum lines, as well as concentric geometry, requirecoaxial tubing of the pressure and vacuum lines.

These and other objects, features and advantages of the presentinvention will be more readily apparent from the detailed description ofthe preferred embodiments set forth below taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatical view of an electroplating apparatus having awafer mounted therein in accordance with the present invention.

FIG. 2 is a partial cross-sectional view of the electroplating apparatusof FIG. 1 in accordance with the present invention.

FIG. 3 is an enlarged cross-sectional view of a region of the clamshellof FIG. 2 in accordance with one embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view of a region of a clamshell inaccordance with an alternative embodiment of the present invention.

FIG. 5 is a top plan view of a cup in accordance with the presentinvention.

FIG. 6 is a cross-sectional view of the cup along the line VI--VI ofFIG. 5.

FIG. 7 is a bottom plan view of a cone in accordance with the presentinvention.

FIG. 8 is a cross-sectional view of the cone along the line VIII--VIIIof FIG. 7.

FIG. 9 is a cross-sectional view of the cone along the line IX--IX ofFIG. 7.

FIG. 10 is a top plan view of a cup in accordance with an alternativeembodiment of the present invention.

FIG. 11 is an enlarged top plan view of a region of the cup of FIG. 10.

FIG. 12 is a top plan view of a contact strip for use in a clamshell inaccordance with the present invention.

FIG. 13 is a cross sectional view of a wafer mounted in a clamshell inaccordance with an alternative embodiment of the present invention.

FIGS. 14A, 14B, 15A, 15B are cross-sectional views of a cup containing awafer in accordance with alternative embodiments of the presentinvention.

FIGS. 16 and 17 are perspective and cross-sectional view, respectively,of a self-contained clamshell and drive in accordance with analternative embodiment of the present invention.

FIG. 18 is a cross-sectional view of the clamshell in the open positionin accordance with this embodiment of the present invention.

FIG. 19 is an enlarged cross-sectional view of a region of the clamshellof FIG. 18.

FIG. 20 is a cross-sectional view of the clamshell while closing inaccordance with this embodiment of the present invention.

FIG. 21 is a cross-sectional view of the clamshell in the closedposition in accordance with this embodiment of the present invention.

FIG. 22 is a perspective view, partially cutaway, of a clamshell anddrive in accordance with another embodiment of the present invention.

FIG. 23 is a perspective view, partially cutaway, of a region XXIII ofFIG. 22.

FIG. 24 is a perspective view, partially cutaway, of a region XXIV ofFIG. 22.

FIG. 25 is a perspective view of a cup in accordance with thisembodiment of the present invention.

FIG. 26 is a top plan view, partially cutaway, of the cup of FIG. 25.

FIG. 27 is a cross-sectional view of the cup along the line XXVII--XXVIIof FIG. 26.

FIG. 28 is an enlarged cross-sectional view of a region XXVIII of FIG.27.

FIG. 29 is a side-plan view of the cup of FIG. 25.

FIG. 30 is an enlarged side-plan view of a region XXX of FIG. 29.

FIG. 31 is a top plan view of a compliant seal in accordance with thisembodiment of the present invention.

FIG. 32 is a cross-sectional view of the compliant seal along the lineXXXII--XXXII of FIG. 31.

FIG. 33 is an enlarged cross-sectional view of a region XXXIII of FIG.32.

FIGS. 34 and 35 are perspective and front plan views, respectively, of asnubber in accordance with this embodiment of the present invention.

FIG. 36 is a side plan view of the snubber of FIG. 34.

FIG. 37 is a rear plan view of the snubber of FIG. 34.

FIG. 38 is a side plan view of a torsionally bent contact in accordancewith this embodiment of the present invention.

FIG. 39 is a top plan view of a contact strip in accordance with thisembodiment of the present invention.

FIGS. 40A and 40B are front perspective views of a contact at variousstages during fabrication from the contact strip of FIG. 39.

FIG. 41 is a top perspective view of a cone in accordance with thisembodiment of the present invention.

FIG. 42 is a bottom perspective view of the cone of FIG. 41.

FIG. 43 is a top plan view of the cone of FIG. 41.

FIG. 44 is a cross-sectional view of the cone along the line XLIV--XLIVof FIG. 43.

FIG. 45 is an enlarged cross-sectional view of a region XLV of FIG. 44.

FIG. 46 is an enlarged cross-sectional view of a region XLVI of FIG. 44.

FIG. 47 is a cross-sectional view of the cone along the lineXLVII--XLVII of FIG. 43.

FIG. 48 is a bottom plan view of the cone of FIG. 41.

FIGS. 49A, 49B, and 50 are top perspective, bottom perspective and topplan views, respectively, of a top plate in accordance with thisembodiment of the present invention.

FIG. 51 is a side plan view of the top plate of FIGS. 49A, 49B.

FIG. 52 is a bottom plan view of the top plate of FIGS. 49A, 49B.

FIG. 53 is a cross-sectional view of the top plate along the lineLIII--LIII of FIG. 52.

FIG. 54 is a side plan view of the top plate of FIGS. 49A, 49B.

FIGS. 55 and 56 are perspective and top plan views of a strut inaccordance with this embodiment of the present invention.

FIG. 57 is a side plan view of the strut of FIG. 55.

FIGS. 58 and 59 are an exploded perspective view, partially cutaway, anda cross-sectional view of the rotary union of FIG. 22.

FIGS. 60, 61 and 62 are cross-sectional views of rotary unions inaccordance with alternative embodiments of the present invention.

FIG. 63 is a flowchart of a process of electroplating a layer on aplating surface of a wafer in accordance with the present invention.

FIGS. 64A and 64B are front and side views of a wet bench with a rackholding the clamshell.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Several elements in the following figures are substantially similar.Therefore similar reference numbers are used to represent similarelements.

FIG. 1 is a diagrammatical view of an electroplating apparatus 30 havinga wafer 36 mounted therein in accordance with the present invention.Apparatus 30 includes a clamshell 33 mounted on a rotatable spindle 38which allows rotation of clamshell 33. Clamshell 33 comprises a cone 32,a cup 34 and a flange 49. Flange 49 has formed therein a plurality ofapertures 49. A flange similar to flange 51 is described in detail inContolini et al., co-filed application Ser. No. 08/970,120, cited above.

During the electroplating cycle, wafer 36 is mounted in cup 34.Clamshell 33 and hence wafer 36 are then placed in a plating bath 43containing a plating solution. As indicated by arrow 53, the platingsolution is continually provided to plating bath 43 by a pump 45.Generally, the plating solution flows upwards to the center of wafer 36and then radially outward and across wafer 36 through apertures 51 asindicated by arrows 55. Of importance, by directing the plating solutiontowards the center of wafer 36, any gas bubbles entrapped on wafer 36are quickly removed through apertures 51. Gas bubble removal is furtherenhanced by rotating clamshell 33 and hence wafer 36.

The plating solution then overflows plating bath 43 to an overflowreservoir 59 as indicated by arrows 61. The plating solution is thenfiltered (not shown) and returned to pump 45 as indicated by arrow 63completing the recirculation of the plating solution.

A DC power supply 65 has a negative output lead electrically connectedto wafer 36 through one or more slip rings, brushes and contacts (notshown). The positive output lead of power supply 65 is electricallyconnected to an anode 67 located in plating bath 43. During use, powersupply 65 biases wafer 36 to have a negative potential relative to anode67 causing an electrical current to flow from anode 67 to wafer 36. (Asused herein, electrical current flows in the same direction as the netpositive ion flux and opposite the net electron flux.) This causes anelectrochemical reaction (e.g. Cu⁺⁺ +2e⁻ =Cu) on wafer 36 which resultsin the deposition of the electrically conductive layer (e.g. copper) onwafer 36. The ion concentration of the plating solution is replenishedduring the plating cycle, for example by dissolving a metallic anode(e.g. Cu=Cu³⁰ + +2e⁻). Shields 69A and 69B (virtual anodes) are providedto shape the electric field between anode 67 and wafer 36. The use andconstruction of anodes and shields are further described in Reid et al.,co-filed application Ser. No. 08/969,196 and Reid et al., co-filedapplication Ser. No. 08/969,269, both cited above.

FIG. 2 is a partial cross-sectional view of apparatus 30 in accordancewith the present invention. Apparatus 30 includes cone 32 and cup 34which in combination form clamshell 33 in which a semiconductor wafer36, typically a silicon wafer, is mounted. Illustratively, the diameterA3 of cup 34 is 14.350 inches (in.).

Cone 32 is attached to rotatable spindle 38. Spindle 38 is supported bya needle bearing 40 and a dual tapered roller bearing 42 which allowspindle 38 to rotate. A motor (not shown) drives spindle 38 by a drivebelt 44. Spindle 38 and hence wafer 36 are typically rotated from 20revolutions per minute (rpms) to 150 rpms during the electroplatingcycle. Rotating wafer 36 prevents bubble entrapment on wafer 36 andimproves electrolyte transport to wafer 36 which, in turn, improves theuniformity of the electroplated layer. Further, the motor has thecapability of rotating spindle 38 at 1000 rpms or greater afterclamshell 33 is removed from the plating solution to sling excessplating solution from clamshell 33 and wafer 36.

Slip rings 46 mounted on and electrically isolated from spindle 38 areelectrically connected to clamshell 33 by wires (not shown) inside ofspindle 38. Slip rings 46 in combination with corresponding brushes 47(each slip ring 46 is in contact with a corresponding brush 47) enableelectrical connection between external electrical components (e.g. powersupply 65 of FIG. 1) and clamshell 33 when spindle 38 is rotating asthose skilled in the art will understand. One or more slip rings 46 aretypically used to provide one or more channels (electrical pathwayselectrically isolated from one another, e.g. a slip ring 46 electricallyconnected to a wire). For example, four or six slip rings 46 are used.Suitable slip ring assemblies are available from Meridian Laboratory,Inc. under the name "ROTOCON" and from Fabricast, Inc. This is asignificant advantage over Brogden (cite above) wherein theconfiguration of the conductor to the contacts through the side facinghandle precludes rotation of the wafer.

Spindle 38 is also fitted with a dual channel rotary union 48 whichenables vacuum and pressurized gas to be provided from external sourcesto clamshell 33 through vacuum and pressure lines (not shown) inside ofspindle 38.

Apparatus 30 is mounted on a rack 35 (shown in FIGS. 64A and 64B) whichallows vertical movement of apparatus 30 to enable clamshell 33 andwafer 36 to be lowered into the plating solution. Apparatus 30 is alsoprovided with a computer controller (not shown) which controls thevarious operations of apparatus 30.

FIG. 3 is an enlarged cross-sectional view of a region 50 of FIG. 2 ofclamshell 33 in accordance with one embodiment of the present invention.Referring to FIG. 3, clamshell 33 is in the closed position, i.e. cone32 is in abutting contact with cup 34 and is in pressing contact withthe backside 56 of wafer 36. Cone 32 and cup 34 are clamped together bypulling a vacuum in region 52 between cone 32 and cup 34. Moreparticularly, cone 32, cup 34 and O-rings 54A, 54B define a region 52 (acavity) between cone 32 and cup 34. Region 52 is evacuated by a vacuumline (not shown) from dual channel rotary union 48 (FIG. 2) to clampcone 32 to cup 34. The use of vacuum to clamp cone 32 to cup 34 ensuresthe two clamping surfaces remain flat and properly mated. This is incontrast to the prior art wherein mechanical clamping significantlyincreases complexity, allows fixture warpage, produces non-uniformsealing and makes automation difficult.

The total force exerted on wafer 36 is determined by the surface areasof cone 32 and cup 34 in region 52. Increasing (decreasing) the surfaceareas increases (decreases) the total force exerted on wafer 36. Anillustrative total force on an eight inch diameter wafer (an 8 in.wafer) is in the range of 100 to 400 pounds and typically is greaterthan 150 pounds.

Cup 34 is fitted with a compliant seal 58 which contacts a perimeterregion of plating surface 60 of wafer 36. (The perimeter region is anarea of plating surface 60 adjacent edge 62 of wafer 36.) Compliant seal58 is typically formed of a relatively soft material preferably having aShore A hardness in the range of 60-80. Suitable materials for compliantseal 58 include KALREZ and VITON synthetics manufactured by Dupont, andCHEMRAZ synthetic manufactured by Green, Tweed.

By clamping cup 34 to cone 32, pressing surface 57 of cone 32 pressesagainst backside 56 of wafer 36. This forces the perimeter region ofplating surface 60 of wafer 36 against compliant seal 58 which forms aseal between cup 34 and plating surface 60. By forming a seal betweencup 34 and plating surface 60, compliant seal 58 prevents contactbetween the plating solution and edge 62 and backside 56 of wafer 36 andthe associated electrolyte contamination of importance, the distance B3from edge 62 of plating surface 60 covered by compliant seal 58(illustratively 0.0600 in.) should be minimized to minimize loss ofuseable area of plating surface 60.

As a secondary measure to prevent contamination of backside 56 of wafer36, an O-ring 64 is located in a channel of pressing surface 57 of cone32. O-ring 64 extends beyond the plane defined by pressing surface 57and is interposed between cone 32 and the backside 56 of wafer 36. Aresulting region 66 is pressurized with a gas from a compressed gas line(not shown), typically dry air or an inert gas such as argon ornitrogen. More particularly, region 66 (a cavity) is defined by cone 32,cup 34 including compliant seal 58, wafer 36 and O-rings 54B, 64. O-ring64 prevents the pressurized gas in region 66 from contacting most of thebackside 56 of wafer 36 and thus eliminates any possible damage to wafer36 from the pressurized gas. Further, by pressurizing region 66, anyinadvertent leak in the seal formed between plating surface 60 of wafer36 and compliant seal 58 results in the escape of pressurized gas fromregion 66 into the plating solution, i.e. prevents the plating solutionfrom entering into region 66 and contaminating edge 62 and backside 56of wafer 36.

Although pressing surface 57 of cone 32 is illustrated as contactingbackside 56 of wafer 36 in FIG. 3, in an alternative embodiment (notshown), O-ring 64 is in pressing contact with backside 56 of wafer 36and pressing surface 57 does not directly contact backside 56. Thisembodiment further reduces possible contamination of backside 56 ofwafer 36 since contact between pressing surface 57 and backside 56 ofwafer 36 is eliminated.

Still referring to FIG. 3, a contact/snubber 68, and more particularly abase section 70 of contact/snubber 68, is bolted to cup 34.Contact/snubber 68 has an extended portion 72 (hereinafter contacts 72)which directly contacts and forms the electrical connection with platingsurface 60 of wafer 36. Of importance, contact/snubber 68 is located inregion 66 so that contact between contact/snubber 68 and the platingsolution is avoided.

Located within cone 32 is a lead 74 which is electrically connected toone or more of slip rings 46 (FIG. 2). Lead 74 is attached to a slidingcontact 76 which extends from cone 32 and forms a sliding electricalconnection with a tab 78 of contact/snubber 68. When a wafer 36 is beingloaded or unloaded, cone 32 is raised relative to cup 34 and theelectrical connection between sliding contact 76 and tab 78 is broken.However, after a wafer 36 is loaded and cone 32 lowered, sliding contact76 re-engages tab 78 reestablishing the electrical connection betweensliding contact 76 and tab 78.

On the outer surface of cup 34 a thief electrode 92 can be positionedadjacent wafer 36. Thief electrode 92 is connected to one or more of thechannels of slip rings 46. During the electroplating cycle, material iselectroplated on thief electrode 92 thereby reducing the tendency of theelectroplated layer on wafer 36 to be thicker adjacent edge 62 of wafer36 as those skilled in the art will understand. Thus, by providing athief electrode 92, uniformity of the electroplated layer on platingsurface 60 of wafer 36 may be improved.

FIG. 4 is an enlarged cross-sectional view of a region of a clamshell33A in accordance with an alternative embodiment of the presentinvention. As shown in FIG. 4, clamshell 33A includes a cone 32A and cup34A. Located within cone 32A is a lead 74A formed of an electricallyconductive material. Lead 74A is sealed to cone 32A by an O-ring 242.Electrically connected to lead 74A is a bent contact 76A having a hook240. As shown in FIG. 4, when cone 32A is lowered, hook 240 engages tab78A making the electrical connection between hook 240 and tab 78A.Further, since contact 76A is displaced upward, contact 76A exerts aspring force which presses hook 240 towards tab 78A enhancing theelectrical connection between hook 240 and tab 78A.

Cone 32A is also provided with a plurality of grooves 248 and, moreparticularly, pressing surface 57A of cone 32A comprises a plurality ofrecessed surface areas 246 which define grooves 248. By forming pressingsurface 57A with a plurality of grooves 248, the total surface area ofcone 32A which contacts backside 56 of wafer 36 is reduced which, inturn, reduces possible contamination of backside 56.

FIG. 5 is a top plan view of a cup 34A in accordance with thisembodiment of the present invention. Shown in FIG. 5 are a plurality ofcontact/snubbers 68A although for clarity only a single contact/snubber68A is labeled. Each contact/snubber 68A includes a tab 78A located atthe center of the contact/snubber 68A and two contacts 72A. As describedabove, tabs 78A make the electrical connection with contact 76A of cone32A (FIG. 4) and contacts 72A make the electrical connection with theplating surface of the wafer (not shown in FIG. 5). Contacts 72A alsocenter the wafer when it is first placed in cup 34A.

Illustrative specifications for various characteristics of cup 34A shownin FIG. 5 are provided in Table 1 below.

                  TABLE 1                                                         ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        C1           7° (10 PLCS)                                              D1           10.600 In.                                                       E1           10.380 In.                                                       F1           9.030 In.                                                        G1           45° X .050 In. CHAMBER (4 PLCS)                           H1           .316 In. WIDE SLOT (2 PLCS)                                      I1           0.1360 In. X .475 In. DEEP 90° Countersink                             X .050 In. DEEP (2 PLCS)                                         ______________________________________                                    

FIG. 6 is a cross-sectional view of cup 34A along the line VI--VI ofFIG. 5 in accordance with this embodiment of the present invention.Illustrative specifications for various characteristics of cup 34A shownin FIG. 6 are provided in Table 2 below.

                  TABLE 2                                                         ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        J1           0.010 In.                                                        K1           0.950 In.                                                        L1           .310 In.                                                         M1           .220 In.                                                         N1           1.480 In.                                                        O1           .145 In.                                                         P1           .750 In.                                                         Q1           .100 In.                                                         R1           .200 In.                                                         S1           4-40 THRD X .37 In. DEEP (20 PLCS)                               T1           09.200 In.                                                       U1           09.100 In.                                                       V1           08.480 In.                                                       W1           08.300 In.                                                       X1           07.640 In.                                                       Y1           08.180 In.                                                       Z1           08.510 In.                                                       A2           08.690 In.                                                       B2           9.030 In.                                                        C2           09.370 In.                                                       D2           09.550 In.                                                       ______________________________________                                    

FIG. 7 is a bottom plan view of a cone 32A in accordance with thisembodiment of the present invention. Illustrative specifications forvarious characteristics of cone 32A shown in FIG. 7 are provided inTable 3 below.

                  TABLE 3                                                         ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        G            .260 In. (6 PLCS)                                                H            8-32 THRD X .50 In. deep,                                                     4 PLCS ON A 1.625 In. bolt circle                                I            4-40 THRD X .37 In. deep,                                                     6 PLCS ON A 5.250 In. bolt circle                                J            4-40 THRD X .37 In. deep,                                                     6 PLCS ON A 7.250 In. bolt circle                                K            45°                                                       L            22.50°                                                    ______________________________________                                    

FIG. 8 is a cross-sectional view of cone 32A along the line VIII--VIIIof FIG. 7 in accordance with this embodiment of the present invention.Shown in FIG. 8 are vacuum passages 260, 262 through which vacuum isprovided to clamp cone 32A to cup 34A (cup 34A is not shown in FIG. 8).Illustrative specifications for various characteristics of cone 32Ashown in FIG. 8 are provided in Table 4 below.

                  TABLE 4                                                         ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        A2           9.0300 In.                                                       B2           0.250 In.                                                        C2           0.093 In. Thru, (2 PLCS)                                         D2           0.136 In. Thru, (Both Sides) TAP                                              8-32 X 0.25 In. deep (2 PLCS)                                    ______________________________________                                    

FIG. 9 is a cross-sectional view of cone 32A along the line IX--IX ofFIG. 7 in accordance with this embodiment of the present invention.Illustrative specifications for various characteristics of cone 32Ashown in FIG. 9 are provided in Table 5 below.

                  TABLE 5                                                         ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        M            08.176 In.                                                       N            07.800 In.                                                       O            .325 In. (7 PLCS)                                                P            02.250 In.                                                       Q            .060 In. (7 PLCS)                                                R            .080 In.                                                         S            .025 In.                                                         T            .750 In.                                                         U            .950 In.                                                         V            1.435 In.                                                        W            1.885 In.                                                        X            9.030 In.                                                        Y            09.850 In.                                                       Z            0.4865 In. X .470 In. deep, (ream) press                                      .1875 In. X .937 In. dowel pin, (2 PLCS)                         A1           .250 In.                                                         B1           1.060 In.                                                        ______________________________________                                    

FIG. 10 is a top plan view of cup 34B in accordance with an alternativeembodiment of the present invention. Cup 34B is fitted with twoalignment holes 80A, 80B through which alignment pins (not shown) extendinto corresponding alignment holes in the cone (not shown). Cup 34B hasa central aperture 81 defined by an inner perimeter 83 of cup 34Bthrough which most of the plating surface of the wafer (not shown) isexposed to the plating solution.

In this embodiment, a plurality of contacts 72B, and more particularly180 contacts 72B are provided to make the electrical connection with theplating surface of the wafer. Typically it is desirable to provide atleast 16 contacts 72B, and in one embodiment 128 contacts 72B areprovided.

FIG. 11 is an enlarged top plan view of a region 94 of cup 34B of FIG.10 in accordance with this embodiment of the present invention.Referring to FIG. 11, adjacent inner perimeter 83 of cup 34B iscompliant seal 58B and adjacent compliant seal 58B are contacts 72B.Also shown is a tab 78B which forms the electrical connection with thecontact of the cone (not shown).

Referring again to FIG. 10, contacts 72B are grouped into banks 84, 86,88 and 90 of contacts 72B. Each bank of contacts 72B is integral to acontact strip (e.g. see contact strip 140 of FIG. 12 described below)which is electrically isolated from the other banks of contacts.Further, each bank of contacts 72B has at least one tab 78B which allowsthe bank to be electrically connected to one channel of slip rings 46(FIG. 2), i.e. allows the bank to be electrically connected to acorresponding one of slip rings 46.

Still referring to FIG. 10, a wafer (not shown) is loaded into cup 34B,plating surface down (into the plane of the paper). Cup 34B is thenclamped to a cone as described above. Then, to test the integrity of theelectrical connection between contacts 72B and the plating surface ofthe wafer, the resistance between each bank and another bank is testedand continuity between these resistances is determined. (The wafer isprovided with a conventional electrically conductive seed layer on theplating surface, e.g. a copper layer on a titanium nitride layer or on atantalum layer). For example, a first resistance between banks 84 and 86is determined and a second resistance between banks 88 and 90 isdetermined and the first and second resistances are compared. If thereis a significant variation in resistance between banks 84, 86, 88 and 90of contacts 72B, then one or more poor electrical connections betweenthe plating surface of the wafer and contacts 72B exists. Generally, avariation in resistance of 20 milli-ohms (mΩ)or more is sufficient tocause a measurable degradation in plating uniformity at 15 milli-ampsper square centimeter (mA/cm²) plating current density. Althoughcontacts 72B are separated into four banks 84, 86, 88 and 90 in FIG. 10,generally contacts 72B are separated in two or more banks of contacts72B. This is in contrast to the dry contact electroplating apparatus ofBrogden (cite above) wherein all of the contacts are electricallyconnected to one another.

FIG. 12 is a top plan view of a contact strip 140 for use in a clamshellin accordance with the present invention. Contact strip 140 is formedfrom an electrically conductive material, typically metal having athickness in the range of approximately 0.002 In. to 0.008 In. Suitableelectrically conductive materials include beryllium, copper, halfhardberyllium-copper, stainless steel, tantalum, gold, platinum, titanium,nickel, rhodium or other corrosion resistant materials. Other suitableelectrically conductive materials include corrosion prone materialscoated with corrosion resistant materials such as those listed above.Illustratively, length A of contact strip 140 is 6.0 in., width B ofcontact strip 140 is 0.700 in., width C of contacts 72C is 0.100 in. andthe spacing D between contacts 72C is 0.100 in. Of importance, to insureuniformity in the electrical potential applied to the wafer (not shown),the voltage drop from end to end of contact strip 140 should not exceedone tenth of an ohm (0.1 ohm) when length A is 6.0 in.

Forming contacts 72C integrally as a contact strip 140 simplifiesmanufacturing and reduces cost compared to forming each contactindividually and then electrically connecting the individual contactstogether. In one embodiment, using conventional techniques, a singlesheet of metal is stamped and then the flat strip is bent to formcontact strip 140.

FIG. 13 is a cross sectional view of a wafer 36 mounted in a clamshell33D in accordance with an alternative embodiment of the presentinvention. Clamshell 33D includes a contact strip comprising contacts72D and snubbers 96. Contacts 72D form the electrical connection withplating surface 60 of wafer 36 as described above. Snubbers 96 centerwafer 36 in cup 34D as follows. Initially, wafer 36 is placed into cup34D and on contacts 72D/compliant seal 58D. Snubbers 96 press on edge 62of wafer 36 (indicated as location 96A) around the entire wafer 36 thuscentering wafer 36. (If wafer 36 is off-center, a first set of snubbers96 will be displaced more than a second set of snubbers 96 opposite thefirst set causing the first set to exert more spring force on wafer edge62 than the second set thus moving and centering wafer 36 until allsnubbers 96 are equally displaced by wafer 36.) Cone 32D is then clampedto cup 34D moving snubbers 96 away from edge 62 of wafer 36 (indicatedby location 96B).

Referring again to FIGS. 3, 4, 11, contacts 72, 72A, 72B, respectively,act similarly to snubbers 96 (FIG. 13) to center wafer 36 andaccordingly snubbers 96 are not provided in these embodiments. Moreparticularly, contacts 72, 72A, 72B (FIGS. 3, 4, 11, respectively) aredisplaced from their normal resting position when the wafer is placedinto the cup and the spring force from the displacement of the contactscenters the wafer. This is in contrast to the prior art wherein offcentering of the wafer results in loss of usable wafer area.

FIGS. 14A, 14B are cross-sectional views of a cup 34E containing a wafer36 in accordance with alternative embodiments of the present invention.Referring to FIG. 14A, cup 34E is formed of an electrically insulatingmaterial such as polyvinylidene fluoride (PVDF) or chlorinated polyvinylchloride (CPVC). (The cone, not shown, can also be formed of the same ora similar insulating material.) The body of compliant seal 58E ismounted in cup 34E and the extending portion of compliant seal 58E whichextends from surface 120 of cup 34E has a thickness T1. FIG. 14B issubstantially similar to FIG. 14A except that compliant seal 58F (FIG.14B) tapers from a first thickness T2 at surface 120 of cup 34E to asecond thickness T1 and then continues to extend to wafer 36 withthickness Ti. Contact 72F has also been modified accordingly.

FIGS. 15A, 15B are cross-sectional views of cups 34G, 34H, respectively,in accordance with alternative embodiments of the present invention.Referring to FIG. 15A, cup 34G is formed of an electrically conductivematerial such as aluminum or stainless steel. Contacts 72G are bolteddirectly to cup 34G. In this manner, voltage can be provided to contacts72G by providing voltage to cup 34G. Cup 34G is coated with anelectrically insulating layer 130, for example is coated with PVDF, toprevent material from being deposited on cup 34G during theelectroplating process. (The cone, not shown, can also be formed of thesame or a similar electrically conductive material and can be coatedwith the same or a similar electrically insulating material). Cup 34H ofFIG. 15B is substantially similar to cup 34G of FIG. 15A except that aportion of cup 34H has been bored out (and a portion of compliant seal58H removed) allowing contacts 72H to be inset into cup 34H.

Referring to FIGS. 15A, 15B, in alternative embodiments (not shown),contacts 72G, 72H are not provided. In these alternatives, the contactsare directly connected to cups 34G, 34H and extend up and pass throughcompliant seals 58G, 58H, respectively, to make the electricalconnection with wafer 36. Illustratively, in these alternatives, thecontacts are pogo pins. As still further alternatives, the contacts canbe fashioned from contact strips and these contact strips can be passedthrough compliant seals 58G, 58H to make the electrical connection withwafer 36. By passing the contacts (or contact strips) through thecompliant seal, both the electrical connection and the seal with thewafer can be formed at the same region of the wafer plating surface.This advantageously allows the unusable surface area (the area which isnot electroplated) of the wafer to be reduced compared to theembodiments wherein the contacts are laterally adjacent the compliantseal.

FIGS. 16 and 17 are perspective and cross-sectional views, respectively,of a self-contained clamshell and drive 100 in accordance with analternative embodiment of the present invention. In this embodiment, cup34I is fixedly attached to spindle 38I by struts 102 and a top plate103. As best shown in FIG. 17, cone 32I is attached to a shaft 104extending into spindle 38I and thereby to spindle 38I. Cone 32I iscapable of vertical movement relative to shaft 104 by a conventional airactuated cylinder 112. Clamshell and drive 100 further includes a motor260 which is in-line with, and rotates, spindle 38I.

Referring now to FIG. 17, running from spindle 38I through top plate 103and struts 102 are electrical leads (wires) 108 which provide theelectrical interconnection with contacts 72I. Although only one lead 108is illustrated, it is understood that a plurality of leads 108 can beprovided depending upon the number of electrical connections required(e.g. depending upon the number of banks of contacts 72I and thiefelectrodes used). Self-contained clamshell and drive 100 advantageouslyallow hard wiring of contacts 72I since leads 108 are provided to cup34I through top plate 103 and struts 102 making breakable contacts (e.g.sliding contact 76 and tab 78 of FIG. 3) unnecessary.

FIG. 18 is a cross-sectional view of the clamshell in the open positionin accordance with this embodiment of the present invention. As shown inFIG. 18, cone 32I is vertically separate from cup 34I, i.e. cone 32I isin the "open position". Cone 32I is kept in the open position byapplying pressurized gas to a region 290 of cylinder 112 throughpressure/vacuum line 292. The pressurized gas is also applied to poppetvalves 298 through pressure/vacuum lines 300. However, since poppetvalves 298 remain closed until they contact cup 34I, poppet valves 298are closed and contain the pressurized gas to pressure/vacuum lines 300.Also shown are wafer push pins 294 which extend from cone 32I beyondpressing surface 57I of cone 32I. Wafer push pins 294 are spring loadedby springs 296.

A wafer (not shown) is loaded into slot 106 between cone 32I and cup 34Iand lowered into cup 34I. Referring now to FIG. 19, wafer 36 is shownsitting in cup 34I. Wafer 36 is centered by snubbers 96I and platingsurface 60 of wafer 36 rests on contacts 72I and is vertically separatedfrom compliant seal 58I.

Referring now to FIG. 20, pressurized gas to pressure/vacuum line 292 isreplaced with vacuum which draws a vacuum in region 290 of cylinder 112.This causes a top portion of cylinder 112, and hence cone 32I, to movedownward as indicated by arrow 302. As cone 32I moves downward, aresulting region 306 of cylinder 112 is vented with atmospheric gasesthrough a vent/pressure line 304 which extends through cone 32I from aside 308 of cone 32I to cylinder 112. Pressure/vacuum lines 300 are alsoevacuated. However, since poppet valves 298 remain closed, the vacuum iscontained to pressure/vacuum lines 300.

FIG. 21 is a cross-sectional view of the clamshell in the closedposition in accordance with this embodiment of the present invention. Asshown in FIG. 21, cone 32I and poppet valves 298 are in abutting contactwith cup 34I and hence poppet valves 298 are open. Since poppet valves298 are open, vacuum from pressure/vacuum lines 300 (which are connectedto pressure/vacuum line 292 which is also evacuated) is applied betweencone 32I and cup 34I, clamping cone 32I to cup 34I. More particularly, aclamping region 52E defined by cone 32I and cup 34I and seals 310, 312is evacuated thereby clamping cone 32I to cup 34I. Illustratively, seals310, 312 are formed of VITON. Advantageously, by shutting off the vacuumand monitoring for any pressure rise, a check is readily performed todetermine if cone 32I is properly clamped to cup 34I.

When the clamshell is in the closed position, pressurized gas is appliedto vent/pressure lines 304 by a pressure line 314 coaxial withpressure/vacuum line 292. This pressurized gas thus pressurizes a region66E in which contacts 72E are located. Advantageously, the integrity ofthe seal between compliant seal 58I and plating surface 60 of wafer 36can be readily checked by shutting off the flow of pressurized gas andmonitoring for any pressure loss. This is a significant advantage overthe prior art, e.g. Brogden (cited above), wherein a poor sealingconnection with the wafer will go undetected until plating solutionleaks and contaminates the contacts, wafer edge and backside.

As shown in FIG. 21, when the clamshell is in the closed position, waferpush pins 294 are also fully retracted into cone 32I and press onbackside 56 of wafer 36. After the clamshell is in the closed position,the entire assembly is then lowered into the plating solution. Afterprocessing, the entire assembly is raised from the plating solution andthe procedure described above and illustrated in FIGS. 18-21 is reversedto unload wafer 36. Wafer push pins 294 prevent wafer 36 from stickingto cone 32I when the clamshell is opened. (Although wafer push pins 294are spring loaded with springs 296, in another embodiment, wafer pushpins 294 are air actuated and springs 296 are not provided.) Ofimportance, self-contained clamshell and drive 100 is well suited forautomation with a robotic arm for inserting and removing wafers.

FIG. 22 is a perspective view, partially cutaway, of a clamshell anddrive 100J in accordance with another embodiment of the presentinvention. Illustrative specifications for the various characteristicsshown in FIG. 22 are provided in Table 6 below.

                  TABLE 6                                                         ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        473          Pin, Dowel, .250 OD, 1.25 LG                                     472          Conductor                                                        471          Conductor                                                        468          Stator, Motor                                                    467          Rotor, Motor                                                     457          Spindle Lower Bearing                                            456          Screw, Under Cut, Phil, #10-32 × 1/2, SS                   455          Set Scr., Soc. 5/16"-18 × 1/2 LG.                          451          Screw, But, Hex, 1/4-20 × 1, T1                            444          Screw, Skt, Hex, 5/16-18 × 2-3/4, SS                       443          Screw, Skt, Hex, 5/16-18 × 2-1/2, SS                       441          Screw, Skt, Hex, 5/16-18 × 1-1/2, SS                       440          Screw, Skt, Hex, 5/16-18 × 1, SS                           439          Screw, Skt, Hex, 5/16-18 × 3/4, SS                         438          Screw, Skt, Hex, #10-32 × 1-1/4, SS                        434          SC Drive Shield                                                  432          Strut Upper Pin                                                  431          Strut Lower Pin                                                  429          Plate, CS Drive Shield                                           428          Motor Mount Ring                                                 426          Strut                                                            425          Top Plate, SC Clamshell                                          423          Head Mount                                                       416          Outer Coaxial Tube                                               415          Inner Coaxial Tube                                               414          Motor Bottom Mount                                               413          Motor Stator Ring                                                412          Motor Top Mount                                                  411          Spindle Bearing Mount                                            410          Spindle                                                          404          Assy, Mounting Bracket                                           403          Assy, Rotary Union                                               402          Assy, Clamshell Cone                                             401          Assy, Clamshell Cup                                              ______________________________________                                    

FIG. 23 is a perspective view, partially cutaway, of a region XXIII ofFIG. 22 in accordance with this embodiment of the present invention.Illustrative specifications for the various characteristics shown inFIG. 23 are provided in Table 7 below.

                  TABLE 7                                                         ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        570          Slip Ring Core                                                   569          Slip Ring Brush                                                  566          Motor Encoder                                                    560          Spindle Upper Bearing                                            554          Set Screw, Soc. #4-40 × 1/8 LG.                            550          Washer, Flat, #4, SST                                            548          Screw, Flat, Hex #10-24 × 1/2, SS                          545          Screw, Skt, Hex, 3/8-16 × 1, SS                            542          Screw, Skt, Hex, 5/16-18 × 1-3/4, SS                       537          Screw, Skt, Hex, #10-24 × 3/4, SS                          536          Screw, Skt, Hex, #4-40 × 1/2, SS                           530          Inner Coaxial Tube Top Insert                                    527          Motor Top Bearing Keeper                                         509          Spindle Spacer                                                   508          Spindle Lock Nut                                                 507          Slip Ring Spacer                                                 506          Slip Ring Sleeve                                                 505          Slip Ring Mount                                                  ______________________________________                                    

FIG. 24 is a perspective view, partially cutaway, of a region XXIV ofFIG. 22 in accordance with this embodiment of the present invention.Illustrative specifications for the various characteristics shown inFIG. 24 are provided in Table 8 below.

                  TABLE 8                                                         ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        665          Cup Seal, Shaft                                                  664          Cup Seal, Piston                                                 663          O-Ring, 1.0491D X .103W, VITON                                   662          O-Ring, 2.8641D X .07W, VITON                                    661          O-Ring, .4891D X .070W, VITON                                    659          O-Ring, .1131D X .070W, VITON                                    658          O-Ring, .8641D X .070W, VITON                                    653          Set Scr, Soc. 1/4"-28 × 3/4 LG.                            652          Set Screw, Soc. #4-40 × 1/4 LG.                            649          Screw, Pan, Phil, #4-40 × 1/4, SS                          647          Screw, Flat, Hex, #6-32 × 1/2, SS                          646          Screw, Flat, Hex, #4-40 × 1/4, SS                          635          Cone Up Contact                                                  633          Hub Lock Screw                                                   624          Conductor Guard                                                  622          Piston Mount Nut                                                 621          PH Piston                                                        620          Inner Coaxial Tube Lower Insert                                  619          Cone Drive Cylinder                                              618          Cylinder Shaft Seal Mount                                        617          Spindle Low Mount/CYL Shaft                                      ______________________________________                                    

FIG. 25 is a perspective view of cup 34J in accordance with thisembodiment of the present invention. Illustrative specifications for thevarious characteristics shown in FIG. 25 are provided in Table 9 below.

                  TABLE 9                                                         ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        F25          Wafer Seal                                                       G25          Screw, Pan, Phil, #6-32 × 1/4, T1                          E25          Screw, Pan, Phil, #6-32 × 1/4, SS                          D25          Wafer Contact                                                    C25          Wafer Snubber                                                    B25          Elect Feed Thru                                                  A25          Flange Cup, SC Clamshell                                         ______________________________________                                    

Note that item B25 of FIG. 25, the electrical feedthrough, is typicallywrapped in an electrically insulating material such as insulating tapeto electrically isolate the feedthrough from the plating solution.Further, the contact and snubber detail is not shown in FIG. 25.

FIG. 26 is a top plan view, partially cutaway, of cup 34J in accordancewith this embodiment of the present invention. Illustrativespecifications for the various characteristics shown in FIG. 26 areprovided in Table 10 below.

                  TABLE 10                                                        ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        P26          .O slashed. 10.550 In.                                           O26          4X .O slashed. .1875 thru (ream) .O slashed. .235 ±                        .002↓ .080                                                N26          4X 1.116 In.                                                     M26          2X 2.249 In.                                                     L26          4X .380 In.                                                      K26          4X 1.625 In.                                                     J26          2.306 ± .003 In.                                              I26          10.140 ± .002 In.                                             H26          5.070 ± .002 In.                                              G26          8X 7.0°                                                   F26          3.5°                                                      E26          4X 155.0°                                                 D26          24X Drill .O slashed..104 ↓ .30 (.340 MAX DP. AT DP                    BOTTOM TAP 6-32UNC)                                              C26          8X 45.0°                                                  B26          22.5°                                                     A26          8X 45.0°                                                  ______________________________________                                    

FIG. 27 is a cross-sectional view of cup 34J along the line XXVII--XXVIIof FIG. 26 in accordance with this embodiment of the present invention.Illustrative specifications for the various characteristics shown inFIG. 27 are provided in Table 11 below. Note the cutaway sectionXXVIB--XXVIB of FIG. 27 is illustrated in FIG. 26

                  TABLE 11                                                        ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        I27          .003 In.                                                         H27          24 X . 521 In.                                                   G27          .O slashed. 8.069 ± .001 In.                                  F27          .O slashed. 8.280 In.                                            E27          .O slashed. 8.480 In.                                            D27          1.611 In.                                                        C27          .O slashed. 7.330 In.                                            B27          .O slashed. 7.530 In.                                            A27          .O slashed. 9.080 In.                                            ______________________________________                                    

FIG. 28 is an enlarged cross-sectional view of a region XXVIII of FIG.27 in accordance with this embodiment of the present invention.Illustrative specifications for the various characteristics shown inFIG. 28 are provided in Table 12 below.

                  TABLE 12                                                        ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        G28          .921 ± .002 In.                                               F28          .275 In.                                                         E28          .150 In.                                                         D28          R .020, .020 DP.                                                 C28          1.005 In.                                                        B28          120X .O slashed. .125 3.0° Apart, Thru                    A28          .353 In.                                                         ______________________________________                                    

FIG. 29 is a side-plan view of cup 34J in accordance with thisembodiment of the present invention. Illustrative specifications for thevarious characteristics shown in FIG. 29 are provided in Table 13 below.Note the cutaway section XXVIC--XXVIC of FIG. 29 is illustrated in FIG.26

                  TABLE 13                                                        ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        H29          .500 In.                                                         G29          .250 In.                                                         F29          4X .O slashed. .2510 (REAM)                                                   ↓ .75                                                     E29          .450 ± .001 In.                                               D29          .900 ± .001 In.                                               C29          .750 In.                                                         B29          1.500 In.                                                        A29          12X 1/4-2ounc thrd                                                            ↓ .780 (bottom tap)                                       ______________________________________                                    

FIG. 30 is an enlarged side-plan view of a region XXX of FIG. 29 inaccordance with this embodiment of the present invention. Illustrativespecifications for the various characteristics shown in FIG. 30 areprovided in Table 14 below.

                  TABLE 14                                                        ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        A30          4X .280 In.                                                      702          Electrical feed through to contacts                              704          Strut mounting holes                                             ______________________________________                                    

FIG. 31 is a top plan view of a compliant seal 58J in accordance withthis embodiment of the present invention. Illustrative specificationsfor the various characteristics shown in FIG. 31 are provided in Table15 below.

                  TABLE 15                                                        ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        A31          .O slashed. 8.48 Ref.                                            ______________________________________                                    

FIG. 32 is a cross-sectional view of compliant seal 58J along the lineXXXII--XXXII of FIG. 31 in accordance with this embodiment of thepresent invention. Illustrative specifications for the variouscharacteristics shown in FIG. 32 are provided in Table 16 below.

                  TABLE 16                                                        ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        I32          .O slashed.7.53 In.                                              H32          R.250 In.                                                        G32          R.031 In.                                                        F32          .100 In.                                                         E32          2X R.015 In.                                                     D32          .091 In.                                                         C32          .275 In.                                                         B32          .230 In.                                                         A32          .475 In.                                                         ______________________________________                                    

FIG. 33 is an enlarged cross-sectional view of a region XXXIII of FIG.32 in accordance with this embodiment of the present invention.Illustrative specifications for the various characteristics shown inFIG. 33 are provided in Table 17 below.

                  TABLE 17                                                        ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        F33          .025 In.                                                         E33          R.010 In.                                                        D33          .007 In.                                                         C33          .047 In.                                                         B33          .020 In.                                                         A33          .040 In.                                                         ______________________________________                                    

FIGS. 34 and 35 are perspective and front plan views, respectively, of asnubber 96J in accordance with this embodiment of the present invention.Illustrative specifications for the various characteristics shown inFIG. 35 are provided in Table 18 below.

                  TABLE 18                                                        ______________________________________                                        CHARACTERISTIC                                                                             SPECIFICATION                                                    ______________________________________                                        H35          4X 45°.0°                                          G35          2X .063 In.                                                      F35          2X .060 In.                                                      E35          .125 In.                                                         D35          1.325 In.                                                        C35          .125 In.                                                         B35          2X .140 In.                                                      A35          Grain                                                            ______________________________________                                    

FIG. 36 is a side plan view of snubber 96J in accordance with thisembodiment of the present invention. Illustrative specifications for thevarious characteristics shown in FIG. 36 are provided in Table 19 below.

                  TABLE 19                                                        ______________________________________                                        CHARACTERISTIC       SPECIFICATION                                            ______________________________________                                        F36                  .10 In.                                                  E36                  2X .215 In.                                              D36                  2X .109 In.                                              C36                  2X R.035 In.                                             B36                  2X .140 In.                                              A36                  R.040 In.                                                ______________________________________                                    

FIG. 37 is a rear plan view of snubber 96J in accordance with thisembodiment of the present invention. Illustrative specifications for thevarious characteristics shown in FIG. 37 are provided in Table 20 below.

                  TABLE 20                                                        ______________________________________                                        CHARACTERISTIC       SPECIFICATION                                            ______________________________________                                        F37                  .035 In.                                                 E37                  .506 In.                                                 D37                  .410 In.                                                 C37                  4X R.070 In.                                             B37                  .440 In.                                                 A37                  .730 In.                                                 ______________________________________                                    

FIG. 38 is a side plan view of a torsionally bent contact 72J inaccordance with this embodiment of the present invention. Contact 72J istorsionally bent and includes a tip 150. Tip 150 has an apex 152 whichprojects upward and a base 154 which projects downward (relative to theplane of the inner perimeter of the central aperture of the cup which isnot shown in FIG. 38). Thus, when a wafer is pressed down on contact 72Jand more particularly on tip 150, tip 150 is bent downward (arrow E) andthe end of tip 150 is simultaneously rotated (arrow F). This causes apex152 to be scraped along the plating surface of the wafer thus enhancingand improving the reliability of the electrical connection betweencontact 72J and the plating surface of the wafer. Illustrativespecifications for the various characteristics shown in FIG. 38 areprovided in Table 21 below.

                  TABLE 21                                                        ______________________________________                                        CHARACTERISTIC       SPECIFICATION                                            ______________________________________                                        E38                  .190 In.                                                 D38                  .150 In.                                                 C38                  115°                                              B38                  100°                                              A38                  .675 In.                                                 ______________________________________                                    

FIG. 39 is a top plan view of contact strip in accordance with thisembodiment of the present invention. Illustrative specifications for thevarious characteristics shown in FIG. 39 are provided in Table 22 below.

                  TABLE 22                                                        ______________________________________                                        CHARACTERISTIC       SPECIFICATION                                            ______________________________________                                        K39                  2X .657 In.                                              J39                  2.746 In.                                                I39                  2X .130 In.                                              H39                  .177 In.                                                 G39                  4X .O slashed..144 In.                                   F39                  2X .370 In.                                              E39                  .570 In.                                                 D39                  .100 In.                                                 C39                  14X .200 In.                                             B39                  15X .100 In.                                             A39                  3.10 In.                                                 ______________________________________                                    

FIGS. 40A and 40B are front perspective views of a contact 72J atvarious stages during fabrication from the contact strip of FIG. 39 inaccordance with this embodiment of the present invention. As shown inFIG. 40A, initially tip 150 is bent. After tip 150 is bent, the entirecontact is torsionally bent as illustrated in FIG. 40B. Illustrativespecifications for the various characteristics shown in FIGS. 40A, 40Bare provided in Table 23 below.

                  TABLE 23                                                        ______________________________________                                        CHARACTERISTIC       SPECIFICATION                                            ______________________________________                                        D40                  Twist 10°                                         C40                  0.040 In.                                                B40                  45°                                               A40                  .020 In.                                                 ______________________________________                                    

FIG. 41 is a top perspective view of a cone 32J in accordance with thisembodiment of the present invention. Illustrative specifications for thevarious characteristics shown in FIG. 41 are provided in Table 24 below.

                  TABLE 24                                                        ______________________________________                                        CHARACTERISTIC   SPECIFICATION                                                ______________________________________                                        D41              Screw, Flat, Hex, #4-40 × 1/4, SS                      C41              Screw, Skt, Hex, #6-32 × 3/4, SS                       B41              Anti-Rotate Dog                                              A41              Cone, SC Clamshell                                           ______________________________________                                    

FIG. 42 is a bottom perspective view of cone 32J in accordance with thisembodiment of the present invention. Illustrative specifications for thevarious characteristics shown in FIG. 42 are provided in Table 25 below.

                  TABLE 25                                                        ______________________________________                                        CHARACTERISTIC   SPECIFICATION                                                ______________________________________                                        E42              Set Screw, Soc. #4-40 × 1/4 LG.                        D42              Screw, Pan, Phil, #6-32 × 1/4, SS                      C42              Wafer Push Leaf Spring                                       B42              Wafer Backing O-ring                                         A42              Wafer Push Pin                                               ______________________________________                                    

FIG. 43 is a top plan view of cone 32J in accordance with thisembodiment of the present invention. Illustrative specifications for thevarious characteristics shown in FIG. 43 are provided in Table 26 below.

                  TABLE 26                                                        ______________________________________                                        CHARACTERISTIC                                                                            SPECIFICATION                                                     ______________________________________                                        L43         .O slashed. .031 Thru                                             K43         4X 45.0°                                                   J43         4X 4-40 THRD ↓ .250 on                                                 a .O slashed. .600 B.C. 90° Apart                          I43         45.0°                                                      H43         .O slashed. 2.158 + .002                                                      -.000                                                             G43         .O slashed. 3.001 + .001                                                      -.000                                                             F43         .O slashed. 10.040 In.                                            E43         .O slashed. 2.500 ± .002 In.                                   D43         48.0°                                                      C43         2.00 In.                                                          B43         48.0°                                                      A43         2X 6-32 THRD ↓ .60.O slashed..375 ↓ .015            ______________________________________                                    

FIG. 44 is a cross-sectional view of cone 32J along the line XLIV--XLIVof FIG. 43 in accordance with this embodiment of the present invention.Illustrative specifications for the various characteristics shown inFIG. 44 are provided in Table 27 below.

                  TABLE 27                                                        ______________________________________                                        CHARACTERISTIC                                                                            SPECIFICATION                                                     ______________________________________                                        L44         .O slashed. .157 + 001                                                        -.000                                                             K44         .O slashed..062 thru C'drill .O slashed..070 ↓ .320                    2-56Unc thrd ↓ .250(bottom tap)                            J44         .O slashed. .312↓ .345 .O slashed..376↓                         .170(Ream)                                                        I44         4.525 In.                                                         H44         .580 + .000                                                                   -.005                                                             G44         1.180 + .005                                                                  -.000                                                             F44         .O slashed. 3.200 In.                                             E44         .O slashed. 7.300 In.                                             D44         .O slashed. 7.875 In.                                             C44         .O slashed. 8.060 ± .001                                       B44         .O slashed. .062 thru drill and tap for 4-40↓ .25          A44         1.144 In.                                                         ______________________________________                                    

FIG. 45 is an enlarged cross-sectional view of a region XLV of FIG. 44in accordance with this embodiment of the present invention.Illustrative specifications for the various characteristics shown inFIG. 45 are provided in Table 28 below.

                  TABLE 28                                                        ______________________________________                                        CHARACTERISTIC       SPECIFICATION                                            ______________________________________                                        H45                  20.0°                                             G45                  .020 In.                                                 F45                  .O slashed.7.475 In.                                     E45                  .097 ± .001 In.                                       D45                  2X R.005 ± .002 In.                                   C45                  2X R.020 In.                                             B45                  .767 ± .003 In.                                       A45                  .845 Ref                                                 ______________________________________                                    

FIG. 46 is an enlarged cross-sectional view of a region XLVI of FIG. 44in accordance with this embodiment of the present invention.Illustrative specifications for the various characteristics shown inFIG. 46 are provided in Table 29 below.

                  TABLE 29                                                        ______________________________________                                        CHARACTERISTIC       SPECIFICATION                                            ______________________________________                                        M46                  2X .116 In.                                              L46                  2X 85.0°                                          K46                  .212 In.                                                 J46                  2X .240 In.                                              I46                  2X .090 In.                                              H46                  2X .210 In.                                              G46                  2X R.015 In.                                             F46                  .020 In.                                                 E46                  .060 In.                                                 D46                  .O slashed. 9.500 In.                                    C46                  .O slashed. 8.600 In.                                    B46                  30.0°                                             A46                  .745 In.                                                 ______________________________________                                    

FIG. 47 is a cross-sectional view of cone 32J along the lineXLVII--XLVII of FIG. 43 in accordance with this embodiment of thepresent invention. Illustrative specifications for the variouscharacteristics shown in FIG. 47 are provided in Table 30 below.

                  TABLE 30                                                        ______________________________________                                        CHARACTERISTIC   SPECIFICATION                                                ______________________________________                                        F47              .595 In.                                                     E47              .003 In.                                                     D47              2X .230 In.                                                  C47              1.440 In.                                                    B47              4X .225 In.                                                  A47              4X .O slashed. .190 thru .O slashed. .332 ↓           ______________________________________                                                         .200                                                     

FIG. 48 is a bottom plan view of cone 32J in accordance with thisembodiment of the present invention. Illustrative specifications for thevarious characteristics shown in FIG. 48 are provided in Table 31 below.

                  TABLE 31                                                        ______________________________________                                        CHARACTERISTIC   SPECIFICATION                                                ______________________________________                                        G48              4X .O slashed. .2510 ↓ .750 (ream)                    F48              4X .500 In.                                                  E48              4X 45.0°                                              D48              8X R.170 In.                                                 C48              4X 1.125 In.                                                 B48              4X 2.300 In.                                                 A48              8X 6-32Unc Thrd ↓ .40 In.                             ______________________________________                                    

FIGS. 49A, 49B, and 50 are top perspective, bottom perspective and topplan views, respectively, of a top plate 103J in accordance with thisembodiment of the present invention. Referring to FIG. 49B, channels 187are provided for the electrical leads (not shown in FIG. 49B, see lead108 in FIG. 17 for example). Illustrative specifications for the variouscharacteristics shown in FIG. 50 are provided in Table 32 below.

                  TABLE 32                                                        ______________________________________                                        CHARACTERISTIC   SPECIFICATION                                                ______________________________________                                        N50              3.320 In.                                                    M50              6.640 In.                                                    L50              4X 155.0°                                             K50              4X 5/16-18Unc Thrd Thru                                      J50              .O slashed. 3.875 ± .001 In.                              I50              .O slashed. 3.250 In.                                        H50              4X 90.0°                                              G50              22.5°                                                 F50              2X 2.360 In.                                                 E50              2X 1.180 In.                                                 D50              22.5°                                                 C50              180.0°                                                B50              2x .O slashed. .2510 (ream)                                                   ↓ .75                                                 A50              10.640 Ref                                                   ______________________________________                                    

FIG. 51 is a side plan view of top plate 103J in accordance with thisembodiment of the present invention. Illustrative specifications for thevarious characteristics shown in FIG. 51 are provided in Table 33 below.

                  TABLE 33                                                        ______________________________________                                        CHARACTERISTIC   SPECIFICATION                                                ______________________________________                                        B51              1.000 In.                                                    A51              2X .800 In.                                                  ______________________________________                                    

FIG. 52 is a bottom plan view of top plate 103J in accordance with thisembodiment of the present invention. Illustrative specifications for thevarious characteristics shown in FIG. 52 are provided in Table 34 below.

                  TABLE 34                                                        ______________________________________                                        CHARACTERISTIC SPECIFICATION                                                  ______________________________________                                        M52            4X 6-32 Thrd ↓.50 C'Sink for #6 FHCS                    L52            4X .500 In.                                                    K52            4X .250 In.                                                    J52            4X .140 In.                                                    I52            4X .125 wide × .130 Deep Slot                            H52            4X .380 In.                                                    G52            4X 1.625 In.                                                   F52            4X R.125 In.                                                   E52            10.140 ± .002 In.                                           D52            2X .250 In.                                                    C52            4X 1.118 Ref                                                   B52            4X 16.0°                                                A52            4X 45.0°                                                ______________________________________                                    

FIG. 53 is a cross-sectional view of top plate 103J along the lineLIII--LIII of FIG. 52 in accordance with this embodiment of the presentinvention. Illustrative specifications for the various characteristicsshown in FIG. 53 are provided in Table 35 below.

                  TABLE 35                                                        ______________________________________                                        CHARACTERISTIC   SPECIFICATION                                                ______________________________________                                        B53              4X .250 In.                                                  A53              4X .250 In.                                                  ______________________________________                                    

FIG. 54 is a side plan view of top plate 103J in accordance with thisembodiment of the present invention. Illustrative specifications for thevarious characteristics shown in FIG. 54 are provided in Table 36 below.

                  TABLE 36                                                        ______________________________________                                        CHARACTERISTIC   SPECIFICATION                                                ______________________________________                                        G54              16X .400 + .002                                                               -.000                                                        F54              4X .O slashed. .2510 (ream)                                                   ↓ .75 In.                                             E54              2X .900 ± .001 In.                                        D54              2X .450 ± .001 In.                                        C54              12 1/4-2ounc thrd                                                             ↓ .75 In.                                             B54              2X .750 In.                                                  A54              2X 1.500 In.                                                 ______________________________________                                    

FIGS. 55 and 56 are perspective and top plan views of a strut 102J inaccordance with this embodiment of the present invention. Referring toFIG. 55, channels 189 of strut 102J are provided for the electricalleads (not shown in FIG. 55, see lead 108 in FIG. 17 for example).Illustrative specifications for the various characteristics shown inFIG. 56 are provided in Table 37 below.

                  TABLE 37                                                        ______________________________________                                        CHARACTERISTIC   SPECIFICATION                                                ______________________________________                                        L56              2X .250 In.                                                  K56              2X .130 In.                                                  J56              .250 In.                                                     I56              6.980 In.                                                    H56              3.490 In.                                                    G56              2X .045 + .005                                                                -.000                                                        F56              2X 45.0° × .130 In.                             E56              1.020 In.                                                    D56              2.040 In.                                                    C56              2X .300 In.                                                  B56              2.205 In.                                                    A56              4.410 In.                                                    ______________________________________                                    

FIG. 57 is a side plan view of strut 102J in accordance with thisembodiment of the present invention. Illustrative specifications for thevarious characteristics shown in FIG. 57 are provided in Table 38 below.

                  TABLE 38                                                        ______________________________________                                        CHARACTERISTIC   SPECIFICATION                                                ______________________________________                                        T57              16X R.130 In.                                                S57              8X .050 In.                                                  R57              .O slashed. .2500 (ream)                                     Q57              4X .O slashed. .258 In.                                      P57              2X .450 In.                                                  O57              2X .900 In.                                                  N57              2X 1.565 In.                                                 M57              2X 3.130 In.                                                 L57              2X 3.190 In.                                                 K57              2X 6.380 In.                                                 J57              8X .400 In.                                                  I57              2X .810 In.                                                  H57              4.200 In.                                                    G57              2X .570 In.                                                  F57              2X 1.500 In.                                                 E57              4X R.187 In.                                                 D57              2X .100 In.                                                  C57              .O slashed. .2500 (ream)                                     B57              2.280 In.                                                    A57              4.560 In.                                                    ______________________________________                                    

FIGS. 58 and 59 are an exploded perspective view, partially cutaway, anda cross-sectional view of rotary union 403 of FIG. 22. Referring toFIGS. 58 and 59, rotary union 403 includes a shaft 720 attached to abracket 722. Shaft 720 is mounted inside of outer housing 724 bybearings 726, 728. During use, bearings 726, 728 allow shaft 720 to beheld stationary by bracket 722 while allowing outer housing 724 and theremainder of rotary union 403 to rotate.

As best seen in FIG. 59, extending through the axial center of shaft 720is a pressure/vacuum passage 732 and offset radially from the axialcenter of shaft 720 is a pressure passage 730. Referring to FIG. 58,pressure passage 730 terminates at an aperture 734 of a surface area 736of shaft 720, surface area 736 being perpendicular to the longitudinalaxis of shaft 720. Pressure/vacuum passage 732 terminates at an aperture738 located in the center of an extended surface area 740 of shaft 720,extended surface area 740 also being perpendicular to the longitudinalaxis of shaft 720. Extended surface area 740 defines an extension 742 ofshaft 720.

Outer housing 724 includes an integral disk 744. (A portion of outerhousing 724 has been cutaway for clarity.) Disk 744 has a disk centralaperture 746. Located between disk 744 and surface area 736 is an outerface seal 752 and a wave compression spring 754. Outer face seal 752 hasa seal central aperture 753 through which extension 742 of shaft 720passes. Wave compression spring 754 is in pressing contact with an uppersurface 756 of disk 744 and a lower surface 760 of outer face seal 752and, further, an upper surface 762 of outer face seal 752 is in pressingcontact with surface area 736. Extending through disk 744 areanti-rotation pins 748, 750. During use, wave compression spring 754presses outer face seal 752 against surface area 736 forming a sealbetween upper surface 762 of outer face seal 752 and surface area 736.Pressurized gas through pressure passage 730 exits aperture 734 andpasses through seal central aperture 753 and through disk centralaperture 746. To prevent the pressurized gas from passing back aroundbetween outer face seal 752 and outer housing 724, the periphery ofouter face seal 752 is fitted with an O-ring 764. However, to the extentthat any pressurized gas leaks past O-ring 764, the pressurized gasescapes through a seal vent 766 (a channel) of outer housing 724, sealvent 766 being located between outer housing 724 and bearings 726, 728.This prevents pressurized gas from passing through bearings 726, 728.

Extending through disk 744 are anti-rotation pins 748, 750. Outer faceseal 752 has corresponding apertures (which extend only partially, notthrough, outer face seal 752) into which anti-rotation pins 748, 750extend. During use, anti-rotation pins 748, 750 prevent outer face seal752 from rotating relative to outer housing 724.

Extending through disk central aperture 746 is an upper extended portion768 including a raised surface area 770 of an inner face seal 772. Apressure/vacuum passage 782 extends longitudinally through inner faceseal 772 from an aperture 784 of raised surface area 770. A lowerextended portion 774 of inner face seal 772 extends into an upperaperture 776 of lower connector 778. Located between inner face seal 772and lower connector 778 is a compression spring 780. Compression spring780 presses inner face seal 772 against shaft 720 forming a seal betweenraised surface area 770 of inner face seal 772 and extended surface area740 of shaft 720.

During use, vacuum through pressure/vacuum passage 732 exits aperture738 and enters aperture 784 and thereby enters and passes throughpressure/vacuum passage 782 of inner face seal 772. (It is understoodthat pressurized gas may be substituted for the vacuum.) To prevent thevacuum from passing back around between inner face seal 772 and lowerconnector 778, upper aperture 776 of lower connector 778 is fitted withan O-ring 786. Inner face seal 772 has two notches, 777A, 777B throughwhich anti-rotation pins 748, 750 pass to prevent inner face seal 772from rotating relative to outer housing 724.

While the vacuum passes through pressure/vacuum passage 782 of innerface seal 772, the pressurized gas (which exits aperture 734 of shaft720) passes around the outside of inner face seal 772 and into apressure passage 790 of lower connector 778 which is offset radiallyfrom the axial center of lower connector 778.

A coaxial tube connector 792 has an extended portion 794 including araised surface area 796 which fits into an inner upper aperture 798 oflower connector 778. (A portion of lower connector 778 has been cutawayfor clarity.) Extending from an aperture 800 of raised surface area 796is a pressure/vacuum passage 802. The vacuum passes into aperture 800and pressure/vacuum passage 802 from pressure/vacuum passage 803 andthus passes through the axial center of tube connector 792 to an innercoaxial tube 804. An O-ring 806 is fitted on extended portion 794 toform a seal between tube connector 792 and lower connector 778preventing the escape of vacuum.

A disk middle portion 808 of tube connector 792 which fits into a innerlower aperture 810 of lower connector 778. A pressure passage 812 passesthrough disk middle portion 808 and is radially offset from the axialcenter of tube connector 792. Pressurized gas from pressure passage 790of lower connector 778 passes through pressure passage 812 and into thespace between inner coaxial tube 804 and an outer coaxial tube 814. AnO-ring 816 is provided between outer coaxial tube 814 and the innerlower aperture 810 to prevent the escape of pressurized gas.

Of importance, rotary union 403 allows both vacuum and pressure to beprovided to the clamshell during rotation through coaxial tubing andmore particularly through inner coaxial 804 and outer coaxial tube 814,respectively. This allows the space required for the tubing to bereduced to that of outer coaxial tube 814 compared to having both tubesin a side by side arrangement. This is particularly advantageous for usein a clamshell apparatus in accordance with the present inventionwherein size constraints of the pressure and vacuum lines, as well asconcentric geometry, requires coaxial tubing of the pressure and vacuumlines.

Although in the above description of rotary union 403, pressurized gasand vacuum are described, it is understood that any combination ofvacuum, pressurized gas or liquid can be provided through rotary union403, for example, pressurized gas can be provided inside of innercoaxial tube 804 and outer coaxial tube 814 at the same time.

FIGS. 60, 61 and 62 are cross-sectional views of rotary unions 403B,403C and 403D, respectively, in accordance with alternative embodimentsof the present invention. Rotary unions 403B, 403C and 403D allowpressure and vacuum to be provided coaxially to a clamshell as discussedabove in relation to rotary union 403 of FIGS. 58 and 59. Accordingly,similar elements as those illustrated in FIGS. 58 and 59 are identifiedby similar reference numbers in FIGS. 60, 61 and 62.

Referring to FIG. 60, in this embodiment, compression spring 780B fitsinside a bored-out portion of inner coaxial tube 804B and vacuum whichpasses through pressure/vacuum passage 782B of inner face seal 772Benters inner coaxial tube 804B directly. Vacuum is prevented fromescaping by an O-ring 786B. Further, in this embodiment, tube connector792 of FIGS. 58, 59 is not provided and pressurized gas is provided tothe region between inner coaxial tube 804B and outer coaxial tube 814Bdirectly through a pressure passage 790B of lower connector 778B.

Referring to FIG. 61, this embodiment is substantially similar to theFIGS. 58, 59 embodiment, with one significant notable difference beingthat tube connector 792 of FIGS. 58, 59 is not provided. Thus, vacuumthrough pressure/vacuum passage 803C of lower connector 778C passesdirectly into inner coaxial tube 804C. Further, pressure from pressurepassage 790C of lower connector 778C is provided directly to the spacebetween inner coaxial tube 804C and outer coaxial tube 814C.

Referring now to FIG. 62, this embodiment is substantially similar tothe FIG. 61 embodiment except that pressure is routed to inner coaxialtube 804D through a pressure passage 832 of lower connector 778D andvacuum is routed to the space between inner coaxial tube 804D and outercoaxial tube 814D through a pressure/vacuum passage 830 of lowerconnector 778D.

FIG. 63 is a flowchart of a process of electroplating a layer on aplating surface of a wafer in accordance with the present invention.Referring to both FIG. 63 and FIG. 3, at step 200, a wafer 36 isinserted into cup 34, plating surface 60 down. At step 202, cup 34 isclamped to cone 32 thereby establishing electrical connection betweencontacts 72 and plating surface 60 of wafer 36 and at the same timeforming the seal between compliant seal 58 and plating surface 60. Atstep 204, continuity in resistance between contacts 72 (or banks ofcontacts, see banks 84, 86, 88, and 90 in FIG. 10 for example) ischecked to establish that on acceptable electrical connection has beenmade between contacts 72 and wafer plating surface 60.

At step 206, clamshell 33 including wafer 36 is lowered into the platingsolution and optionally, at step 208, clamshell 33 is rotated. At step210, voltage is applied to contacts 72 thereby causing a layer, e.g.copper, to be electroplated on plating surface 60 of wafer 36. At step212, the voltage to contacts 72 is turned off thereby preventing furtherelectroplating and, at step 214, clamshell 33 is removed from theplating solution.

At step 216, clamshell 33 is spun at high rpm to sling off excessplating solution from clamshell 33 and wafer 36. At step 218, cup 34 isunclamped from cone 32 and, at step 220, wafer 36 is removed from cup34. At this point, returning to step 200, another wafer 36 to be treatedis loaded into cup 34 and the process is repeated.

Having thus described the preferred embodiments, persons skilled in theart will recognize that changes may be made in form and detail withoutdeparting from the spirit and scope of the invention. For example,referring to FIG. 3, cup 34 can be clamped to cone 32 using mechanicalmeans instead of by using a vacuum. In addition, although the substrateis described and illustrated as a circular wafer having an electricallyconductive seed layer on the plating surface, any substrate having anelectrically conductive layer on a substantially planar surface or anyelectrically conductive substrate having a substantially planar surfacecan be treated. For example, a wafer with a flat can be treated.Further, instead of electroplating a layer on a substrate, the systemcan be used to electrochemically etch or polish a layer on a substrate.Thus the invention is limited only by the following claims.

We claim:
 1. An apparatus for treating a surface of a substratecomprising:a cup having a central aperture defined by an innerperimeter; a compliant seal adjacent said inner perimeter, saidcompliant seal being for pressing against said substrate; a plurality ofelectrical contacts adjacent said compliant seal for making electricalcontact with said substrate; a cone attached to a rotatable spindle,wherein said cone and said cup define a first cavity, said plurality ofcontacts being located in said first cavity; said first cavitycontaining a pressurized gas.
 2. The apparatus of claim 1 furthercomprising:bearings for supporting said spindle; and a motor forrotating said spindle.
 3. The apparatus of claim 1 furthercomprising:one or more slip rings on said spindle; and one or morebrushes for contact with corresponding ones of said slip rings.
 4. Theapparatus of claim 1 further comprising a rotary union mounted to saidspindle.
 5. The apparatus of claim 1 further comprising a rack whichallows vertical movement of said apparatus.
 6. The apparatus of claim 1wherein said cone is in abutting contact with said cup, said cone andsaid cup defining a second cavity therebetween, said apparatus furthercomprising a vacuum line for evacuating said second cavity.
 7. Theapparatus of claim 6 further comprising a first O-ring and a secondO-ring, said second cavity being further defined by said first O-ringand said second O-ring.
 8. The apparatus of claim 1 wherein saidcompliant seal is formed of a material having a shore A hardness in therange of 60-80.
 9. The apparatus of claim 8 wherein said compliant sealis formed of a material consisting of synthetic rubber.
 10. Theapparatus of claim 1 wherein said cone comprises a pressing surface forpressing said substrate against said compliant seal.
 11. The apparatusof claim 10 further comprising a third O-ring located in a channel ofsaid pressing surface, said third O-ring extending beyond the planedefined by said pressing surface.
 12. The apparatus of claim 1 furthercomprising a contact strip comprising said plurality of contacts and abase section, said base section being attached to said cup.
 13. Theapparatus of claim 12 wherein said contact strip further comprises atab, said apparatus further comprising a sliding contact extending fromsaid cone aligned to make contact with said tab when said cone and saidcup are in abutting contact.
 14. The apparatus of claim 12 wherein saidplurality of contacts are bent from said base section, said contactshaving a normal resting position, said contacts exerting a spring forcewhen displaced from said normal resting position.
 15. The apparatus ofclaim 1 further comprising a thief electrode mounted on an outer surfaceof said cup.
 16. The apparatus of claim 1 further comprising at leastone alignment pin, said cup and said cone each having at least onecorresponding alignment hole.
 17. The apparatus of claim 1 wherein saidplurality of contacts are grouped into at least two banks of contacts,each of said banks being electrically isolated for the other of saidbanks.
 18. The apparatus of claim 1 further comprising snubbers forcentering said substrate in said cup.
 19. The apparatus of claim 1wherein said cup is attached to said spindle, said apparatus furthercomprising a shaft extending into said spindle, said cone capable ofvertical movement along said shaft.
 20. The apparatus of claim 19further comprising an air actuated cylinder which moves said cone alongsaid shaft.
 21. The apparatus of claim 19 further comprising at leastone lead extending from said spindle to said cup, said at least one leadbeing electrically connected to said plurality of contacts.
 22. Theapparatus of claim 19 further comprising at least one poppet valve onsaid cone.
 23. The apparatus of claim 1 wherein said cup comprises anelectrically insulating material.
 24. The apparatus of claim 1 whereinsaid cup comprises an electrically conductive material having anelectrically insulating coating.
 25. The apparatus of claim 1, whereineach of said plurality of contacts is torsionally bent so that an apexof a tip of each contact projects upward and a base of said tip pointsdownward relative to a plane defined by said inner perimeter.
 26. Theapparatus of claim 1 further comprising a compressed gas line forsupplying said pressurized gas to said first cavity.
 27. The apparatusof claim 1 further comprising a bath containing an electroplatingsolution.
 28. The apparatus of claim 27 wherein said electroplatingsolution comprises metal ions.
 29. The apparatus of claim 28 whereinsaid electroplating solution comprises copper ions.
 30. The apparatus ofclaim 27 further comprising an anode immersed in said electroplatingsolution.
 31. The apparatus of claim 30 further comprising a powersupply for biasing said anode positive and said electrical contactsnegative.
 32. The apparatus of claim 31 comprising a conductive pathbetween said power supply and said electrical contacts, said conductivepath comprising a slip ring and a brush.
 33. The apparatus of claim 31comprising a substrate to be electroplated, said compliant seal being incontact with a perimeter region of said substrate, said substrate beingurged by said compliant seal against said cone.
 34. The apparatus ofclaim 33 wherein contact between said compliant seal and said perimeterregion of said substrate prevents said electroplating solution fromentering said first cavity.
 35. The apparatus of claim 33 wherein saidsubstrate comprises a semiconductor wafer.